Seven years ago, he took on the toughest task in TV. As the showrunner takes his last regular trip in the Tardis, we look back at his time on the fantasy favourite – from brain-twisting plots to genius collaborations

It was everyone’s favourite small town crime drama – a slow-build whodunnit in a stunning setting that owed as much to Agatha Christie as it did to Scandi noir. We look back at the twists, red herrings, cliffs and cliffhangers of Broadchurch